src/sage/schemes/berkovich/berkovich_cp_element.py: Fix up

Author: Matthias Koeppe

src/sage/schemes/berkovich/berkovich_cp_element.py

@@ -37,7 +37,7 @@
 from sage.structure.element import Element
 from sage.structure.element import Expression
 import sage.rings.abc
-from sage.rings.real_mpfr import RR, is_RealNumber
+from sage.rings.real_mpfr import RR, RealNumber
 from sage.rings.padics.padic_generic_element import pAdicGenericElement
 from sage.rings.padics.padic_base_generic import pAdicBaseGeneric
 from sage.schemes.projective.projective_space import ProjectiveSpace